1. Field of the Invention
The present invention relates to novel pyrimidine or triazine derivatives and their salts as well as herbicidal compositions containing said pyrimidine or triazine derivatives or their salts which can be applied to paddy fields, upland fields or non-agricultural fields.
2. Discussion of Background
Heretofore, it is known that a compound having the formula, ##STR2## (wherein X' is a halogen atom, a lower alkyl group or lower alkoxy group, R is a hydrogen atom or a benzyl group, and n is an integer of 0, 1 or 2) has a herbicidal activity (Japanese Unexamined Patent Publication No. 250366/1989).
However, the herbicidal effect of the compound disclosed in the above patent publication is not always satisfactory, and a compound achieving a better herbicidal effect is demanded.
We have further studied about pyrimidine or triazine type compounds, aiming at developing a more improved compound. As a result of the study, the present inventors have found that a pyrimidine or triazine derivative having a trifluoromethanesulfonyloxy group, an ethenyl group which may optionally be substituted or an ethynyl group which may optionally be substituted on the benzene ring in place of a phenoxy group, achieves an excellent herbicidal effect on annual and perennial weeds in comparison with the compounds disclosed in the above cited Japanese publication, and have completed the present invention.